Combination weighing system

Abstract

A novel combination weighing system which substantially reduces the necessary time for each cycle of operation as compared with the conventional combination weighing system. The system involves sampling a weight indicative signal at a predetermined time point prior to each weighing unit reading stabilization, calculating from each unstable weight indicative signal an estimated stable weight indicative value, executing a combination operation using the estimated stable weight indication values, storing those combinations obtained which satisfy a predetermined weight condition, and calculating the sum weights of the stored combinations using weight indicative signals obtained after stabilization of the weighing units to select a combination whose sum weight satisfies the predetermined weight condition.

I claim: 
     
       1. A combination weighing method, comprising the steps of: loading each of a plurality of weighing units with products to be weighed and sampling the resultant weight indicative signals before they become stable,   subtracting a predetermined estimated deviation from each of said sampled unstable weight indicative signals to calculate an estimated value of the weight indicative signal having become stable,   effecting predetermined combination arithmetic operations with said calculated estimated values and storing the resultant information indicative of all combinations whose sum weights satisfy a predetermined weight condition,   summing said sampled stable weight indicative signals in accordance with said stored combinations to select from said stored combinations a combination whose sum weight satisfies a predetermined weight condition.   
     
     
       2. The method according to claim 1, wherein the difference between said unstable weight indicative signal and said stable weight indicative signal is calculated and then used in place of said predetermined estimated deviation. 
     
     
       3. A combination weighing device, comprising: a plurality of weighing units for weighing product, each unit being adapted to produce a weight indicative signal,   means for sampling said weight indicative signals before they become stable after loading of said weighing units,   means for subtracting a predetermined estimated deviation from each of said sampled unstable weight indicative signals to calculate an estimated value of said weight indicative signal having become stable,   means for effecting predetermined combination arithmetic operations with said calculated estimated values and storing the resultant information indicative of all combinations whose sum weights satisfy a predetermined weight condition,   means for sampling said weight indicative signals after they become stable, and   means for summing said sampled stable weight indicative signals in accordance with said stored combinations to select from said stored combinations a combination whose sum weight satisfies a predetermined weight condition.   
     
     
       4. The device according to claim 3, wherein said device further comprises means for calculating the difference between said unstable weight indicative signal and said stable weight indicative signal, and means for substituting said calculated difference for said predetermined estimated deviation. 
     
     
       5. The device according to claim 3, wherein said combination selecting means include means for selecting a combination whose sum weight satisfies a second weight condition in addition to said predetermined weight condition. 
     
     
       6. A combination weighing method comprising the steps of: loading a plurality of weighing units with product to be weighed, each unit being adapted to generate a signal indicative of the weight of product on the unit, said weight-indicative signal being unstable for a period of time after the unit is loaded;   sampling the unstable weight-indicative signals of the weighing units;   calculating from each unstable weight-indicative signal an estimated stable weight-indicative value; and   effecting combination arithmetic operations using said estimated stable weight-indicative values to obtain information indicative of one or more combinations each having a sum weight which satisfies a predetermined weight condition.   
     
     
       7. The method of claim 6 further comprising the steps of: storing said information indicative of said one or more combinations; sampling said weight-indicative signals after they become stable; and   effecting combination arithmetic operations in accordance with said one or more combinations using said stable weight-indicative signals to obtain information indicative of the sum weights of said one or more combinations to select therefrom a combination having a sum weight which satisfies a predetermined weight condition.   
     
     
       8. The method of claim 7 wherein said estimated stable weight-indicative value is calculated by subtracting a predetermined estimated deviation from said sampled unstable weight-indicative signal. 
     
     
       9. The method of claim 8 wherein, in carrying out said step of effecting combination arithmetic operations using said stable weight-indicative signals, said predetermined estimated deviation is replaced by the difference between said unstable weight-indicative signal and said stable weight-indicative signal.